Optoelectronic camera and method for image formatting in the same

ABSTRACT

An optoelectronic camera comprises an objective system formed by a number of optical active structures (L), particularly refractive structures in the form of microlenses or lenslets provided in an array. A detector device (D) is assigned to the lens array and comprises detectors (D n ) formed by sensor elements (E) which define pixels in the optical image. Each detector (D n ) defines a sample of the optical image and optimally all samples are used to generate a digital image. The optoelectronic camera may be realized as a color image camera, particularly for recording images in an RGB system. In a method for digital electronic formatting of an image recorded with the optoelectronic camera, zoom and pan functions are implemented in the camera.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/NO98/00339 which has an Internationalfiling date of Nov. 13, 1998 which designated the United States ofAmerica.

The present invention concerns an optoelectronic camera comprising anoptical objective system for imaging a scene recorded by the camera asan optical image substantially in an image plane of the objectivesystem, an optoelectronic detector device substantially provided in theimage plane for detecting the optical image and on basis of thedetection outputting output signals, a processor device connected withthe detector device for converting and processing the output signals ofthe detector device in order to reproduce the detected image in digitalform and possibly for displaying this in real time on a display deviceoptionally provided in the camera and connected with the processordevice, and a memory device connected with the processor device forstoring the digital image for displaying on the optional display devicewhich also may be connected with the memory device, or for storing,displaying or possible additional processing on external devices adaptedfor these purposes and whereto the camera temporarily or permanently isconnected.

The present invention also concerns an optoelectronic camera,particularly for recording colour images and even more particularly forrecording colour images in an RGB system, comprising an opticalobjective system for imaging a scene recorded by the camera as anoptical image substantially in an image plane of the objective system,an optoelectronic detector device substantially provided in the imageplane for detecting the optical image and on basis of the detectionoutputting output signals, a processor device connected with thedetector device for converting and processing the output signals of thedetector device in order to reproduce the detected image in digital formand possibly for displaying this in real time on a display deviceoptionally provided in the camera and connected with the processordevice, and a memory device connected with the processor device forstoring the digital image for displaying on the optional display devicewhich also may be connected with the memory device, or for storing,displaying or possible additional processing on external devices adaptedfor these purposes and whereto the camera temporarily or permanently isconnected. Finally, the present invention concerns a method for digitalelectronic formatting of a recorded full-format optical image in anoptoelectronic camera according to any of the claims 1-32 or any of theclaims 33-37, wherein the recorded optical image is stored as a digitalimage in a memory in a processor device provided in the camera and maybe displayed on a display device connected to the processor device.

Very generally the invention concerns optoelectronic cameras which aresuited for recording of still images as well as cinematographic images.including video images. The optoelectronic cameras according to theinvention are realized such that they can be made as cheap miniaturecameras with an extremely flat form factor.

After the launch of charge-coupled components (CCD), electronicphotography is being applied in almost all fields in the imagingtechnology from the most demanding scientific applications such as inastronomical photography with recording of still images under extremelylow light intensities and to applications for mass markets such as homevideo and area surveillance. Up to recently optoelectronic cameradevices almost without exception have been based on the use ofcharge-coupled components (CCD), while other types, for instancecharge-injected components (CID) have gained a certain use in particularapplications, mostly of scientific nature. The basis for use of CCD fordetection and implementation of optoelectronic cameras is extensivelydiscussed in scientific and commercial literature and shall in thefollowing hence be regarded as well-known to persons skilled in the art.

Even if it has been a great success, the CCD technology inoptoelectronic cameras causes a number of disadvantages which has anegative effect on the possible use of CCD and miniaturized cheapbattery-driven optoelectronic cameras. The silicon-based CCD chip isrelatively costly to fabricate, it requires several different drivevoltages and consumes relatively much current. In the course of the lastyears a new class of components called active pixel sensors (APS) hasappeared to be strong competitors to the CCD technology, particularly inapplications which do not require the absolute maximum image quality.The APS-based optoelectronic detectors can be made with low cost bymeans of standard CMOS technology and permits integration of a number offunctions such as light detection, signal conditioning, power supply andinterfacing on the same chip. In addition to the possibility of a verylow cost, low power consumption and compact physical realization, theAPS detectors may be realized such that processing of the imageinformation is obtained directly on the detector chip, including forinstance thresholding, contour determination etc. For certain types ofapplications APS detectors may give fast random access to the selectedpixels or groups of pixels, in contrast with CCD-based detectors whichrequire serial readout of whole rows of pixels at one time.

Commercial applications of APS-based miniature device have emergedwithin a number of areas, either supplanting other technologies orgenerating wholly new products. An instance of the first is the use insurveillance cameras, an instance of the latter is the use in toys. Dueto the particular properties of the APS detectors recent development hasled to optoelectronic cameras with very small dimensions. Such so-called“on chip”-cameras may be obtained commercially from a number ofcompanies, for instance VLSI Vision, Scotland, firms in Sweden andPhotobit, U.S.A. A camera which may be accomodated in fountain penformat was recently demonstrated by CSEM, Switzerland.

A common denominator for all optoelectronic camera types is an opticalsystem which creates an acceptable optical image on the light-sensitivedetector surface. This poses a problem when it is desired to miniaturizeoptoelectronic cameras regardless of the type of optoelectronic sensor(CCD, CID, APS, diode array . . . ) to be used. The problem becomesparticularly accentuated if the available axial length (the distancealong the optical axis from the front of the camera lens andtherethrough to the back of the detector chip) of the camera isrestricted, i.e. when it is desirable to manufacture a flat camera, asthe contribution from the imaging system to this distance is the sum ofthe lens thickness and the back focal length (BFL), something whichindicates that a lenslet or microlens with a very short axial dimensionand very short focal length might be used to provide a flat camerasolution. However, up to now really flat miniaturized optoelectroniccameras based on this principle have not emerged.

As is to be discussed in the following, the main reason for thissubstantially is not to be found in the optics used and which generatesthe optical image. Even if the resolution in the last instance islimited by diffraction, there is another delimiting factor which to amuch larger extent finds expression in the present context, namely therestricted spatial resolution which may be obtained in the image plane,particularly with optoelectronic detector arrays. In order to betterilluminate the logical step in the development which has led to thepresent invention, there shall in the following be given a simple basicanalysis of the drawbacks of the prior art.

The quality of the optical image will depend on the lens constructionand is, as mentioned, in the last instance, limited by diffraction. Inorder to simplify the analysis it shall be supposed that light ismonochromatic green, for instance with a wavelength of 555 nm, and thatthe lens is very thin and diffraction-limited. The spatial resolution inthe image plane is then given by

w=0.61λ/N _(A)  (1)

wherein λ is the light's wavelength and the numerical aperture N_(A)defined as

N_(A)=n sinα.  (2)

Here n is the refraction index in the image space and α the half angleof the edge rays in the image space.

The resolution is in principle independent of the physical size of thelens. With realistic values for the numerical aperture N_(A), theresolution, however, is typically comparable to the light's wavelength.This implies that an image which shall contain M resolved elements(M=n_(x)n_(y), where n_(x) and n_(y) is the number of resolved elementsalong respectively the x and y axis) must cover an area in the imageplane which cannot be less than

A=M w²=n_(x),n_(y), w².  (3)

Here w is the resolution as defined in equation (1) above.

The field of view of the lenses in combination with the lineardimensions n_(x), w and n_(y), w for the image defines the focal lengthof the lens and hence the physical size of the latter. The field of viewis defined by the half angle θ of arrays striking the extreme edge ofthe optical image, at which location the linear distance to the opticalaxis is given by

d/2=(n _(x) ² +n _(y) ²)^(1/2) , w/2  (4)

Denoting the image distance by s′, one has

s′=d/(2tgθ)=(n _(x) ² +n _(y) ²)^(1/2) w/(2tgθ)  (5)

For typical imaging cases the focal length for the lens is only slightlyless than the image distance s′, i.e.

 f≅s′  (6)

If numerical values are inserted for instance w=0.5 μm, n_(x)=n_(y)=10³,i.e. M=10⁶, θ=19.3°, one obtains f≅s′=1.01 mm.

A microlens with this focal length has typically comparable lineardimensions and it will be realized that a truly miniaturized flat cameramay be within reach, and offering a resolution of 1 million pixels.

Unfortunately the requirement that the resolution w shall be 0.5 μm suchas defined above for the recording medium in the image plane, is verydifficult to realize and far beyond what may be implemented withpixelated optoelectronic image sensors, CCD and APS detectors accordingto prior art has a pixel pitch at least ten times the resolution wassumed above, something which implies that the focal length and thelinear dimensions of the lens shall lie in the range from 10 mm andupwards. Evidently the linear size of the camera depends explicitly ofthe desired image quality, i.e. on the detail of resolution in the imageand of whether it is desirable with a monochromatic image or a fullcolour image. Hence optoelectronic cameras with dimensions along theoptical axis in the range of 1 cm may be implemented. This cannot,however, be regarded as being particularly flat. Smaller dimensions arepossible, but entails an impaired image quality. For instances of“on-chip-camera” concepts which exploit CMOS processors to manufactureoptoelectronic camera devices with low costs and/or for particularpurposes, reference shall be made to literature from e.g. Photobit.U.S.A; IVP, Sweden; VLSI Vision, Great Britain; CSEM, Switzerland; andIMEC, Belgium. For a review of imaging techniques with the use ofCMOS-technology, reference may for instance be made to J. Zarnowski & M.Pace, “Imaging options expand with CMOS technology”, Laser Focus World,pp. 125-130 (June 1997).

The main purpose of the present invention is to provide anoptoelectronic camera which may be used for recording still images,cinematographic images or video images with high image quality andbeyond all with high spatial resolution, while the total profile of thecamera appears as very flat and the drawbacks which are linked with theabove-mentioned prior art are avoided, and then particularly that theimage resolution scales with the physical size, particularly the axiallength of the optical imaging system.

It is also the object of the invention to provide an optoelectroniccamera which may be realized as a relatively thin layer, typically inthe size range of 1-3 mm thickness on flat or curved surfaces.

Further it is an object of the invention to provide an optoelectroniccamera with a number of specific spatial and spectral imagingcharacteristics, including controlled resolution of the optical image inone or more areas in the image or along one or more axes in the imageplane, an extremely large field of view, including up to a global field(4π steradians), spatially resolved chromatic or spectral analysis,full-colour images or imaging in one or more wavelength bands fromultraviolet to infrared and parallaxis-based imaging with thepossibility of spatial detection and analysis.

Yet further it is also an object of the invention to provide anoptoelectronic camera with imaging solutions which exploitlight-detecting elements and circuits realized in optoelectronictechnology on large surfaces. Such technology will allow anoptoelectronic camera according to the invention to be manufactured withparticular low cost. Finally it is a special object of the inventionthat the optoelectronic camera shall be realized with the use of thindevices based on amorphous or polycrystalline inorganic semiconductorsor organic semiconductors based on polymers or oligomers. An example ofthe application of such material shall be components in the form offlexible plastic sheets, realized as thin cards which may be attached toflat and curved surfaces.

It is also a special object of the present invention to be able torealize ultraminiaturized optoelectronic cameras by using arrays ofquasi-monochromatic microlenses as the optical active structures in thecamera.

The above objects are realized according to the invention with anoptoelectronic camera which is characterized in that the cameraobjective system is formed by an array of two or more optical activestructures (L), that each optical active structure is adapted forgenerating optical images of the recorded scene on areas of theobjective system image plane uniquely assigned to the respective opticalactive structure, that at least one optoelectronic detector is providedfor each optical active structure in its respective assigned area orimage plane, all detectors being included in the detector device of thecamera, that each detector comprises at least one sensor elementuniquely defining a pixel of the optical image, the area of the pixelsubstantially being determined by the area of the separate definingsensor element, and that each detector is adapted for defining a sampleof the optical image with a number of pixels in each sample determinedby a number of sensor elements in the defining detector, the digitalimage optimally being generated by all samples and with a spatialresolution determined by the number of pixels in distinct positions inthe optical image defined by the sensor elements.

Advantageously the optical active structures in this connection arerefractive structures or diffractive structures or reflective structuresor combinations of such structures.

Particular it is advantageous that the refractive or diffractivestructures are realized as lenslets with a diameter of at most 3 mm.

It is also advantageous when the total number of distinctly definedpixels in the optical image is equal to the total number of sensorelements in the detector device, such that a one-to-one relation betweena given pixel and its defining sensor element in this case is present,whereby the digital image may be generated by a full sampling of theoptical image or that the total number of distinctly defined pixels inthe optical image is smaller than the total number of sensor elements inthe detector device, such that a one-to-many relation between a givenpixel and its defining sensor element or sensor elements in this case ispresent, whereby the digital image may be generated by an oversamplingof the optical image. It is advantageous that the optoelectronic cameracomprises one or more spatial filters provided in front of the objectivesystem and/or between the objective system and the detector device, saidspatial filter perferably being a spatial light-modulator and particularin that connection a controllable electrooptical light-modulator.

It is also advantageous when the optoelectronic camera according to theinvention comprises one or more optical filter means provided in frontof the objective system and/or between the objective system and thedetector device. Preferably the optical filter means then may compriseseparate, spectral-selective filters which separately are assigned toeither each optical active structure or groups of optical activestructures, or to the detector or detectors of the detector deviceassigned to each optical active structure.

Particularly the optical filter means may be adapted for transmitting intwo or more separate wavelength bands by each spectral-selective filtertransmitting in a separate wavelength band, the number of filters whichtransmits in each of the separate wavelength bands substantially beingidentical. The separate wavelength bands may then preferably be selectedsuch that the optical filter means forms a primary colour filter meansor an RGB filter means or such that the optical filter means forms acomplementary colour filter means.

In some embodiments the spectral-selective filter advantageously may berealized as a strip filter which is adapted for transmitting in two ormore separate wavelength bands by each strip transmitting in a givenwavelength band. Preferably each strip in a strip filter may then beassigned to a respective row or column of sensor elements in thedetector or detectors and each strip filter may further be realized as aprimary colour filter or an RGB filter.

It may according to the invention also be advantageous that thespectral-selective filter is a mosaic filter which is adapted fortransmitting in two or more separate wavelength bands by each filtersegment in the mosaic filter transmitting in a given wavelength band,the number of filter segments which transmits in each of the wavelengthbands substantially being identical, and preferably each filter segmentsin a mosaic filter then assigned to a respective sensor element orrespective sensor elements in the detector or detectors. Particularlymay then each mosaic filter preferably be a complementary colour filter.

It is according to the invention advantageous that the detector devicecomprises detectors realized in one of the following technologies, viz.CCD (charge-coupled device) technology, CID (charge-injected device)technology, APS (active pixel sensor) technology or PMSA (sensor arrayin passive matrix) technology. Wherein the detector is realized in PMSAtechnology it is according to the invention advantageous that thedetector is realized as a thin-film component or a hybrid component, andthat the detector is adapted for parallel read-out of the output signalsfrom the sensor elements over a passive electrode array for uniqueaddressing of each separate sensor element, as the detector in this casepreferably may be made wholly or partly of organic semiconducting orelectrical isolating materials, including plastic materials andsemiconducting oligomers or polymers.

It is according to the invention advantageous that the optical activestructures are realized with a determined chromatic aberration ordispersion, such that each optical active structure for two or moreseparate wavelength bands spectral-selectively generates the opticalimage in each wavelength band substantially on correspondingsubstantially congruent image planes superpositioned spaced apart in theray direction, and that for each optical active structure in each ofthese image planes a detector for spectral selective detection of theoptical image is provided such that for each optical active structure oneach image plane a sample in the spatial domain and a sample in thefrequency domain are defined, the resolution in the frequency domainsubstantially being determined by the number of separate wavelengthbands with a respective assigned detector, whereby the optical imagedetected by the detector device may be generated as a multispectraldigital colour image with the use of a selected suitable colour system.In that connection it may for each optical active structure preferablybe provided three separate superpositioned detectors, respectively inthe image plane for three separate wavelength bands assigned to athree-colour system.

Further the above-mentioned objects are realized according to thepresent invention with an optoelectronic camera which is characterizedin that that the camera objective system is formed by an array of two ormore optical active structures, that each optical active structure has adetermined chromatic aberration or dispersion such that the location ofits focal point depends on the wavelength of the light, that eachoptical structure is adapted for generating spectral-selectively opticalimages of the recorded scene on areas of three separate superpositionedimage planes of the objective system, said areas being uniquely assignedto respective optical active structures, a first image plane forming afirst optical image in a wavelength band in the blue portion of thespectrum, and a second image plane a second optical image in awavelength band in the green portion of the spectrum and a third imageplane a third optical image in a wavelength band in the red portion ofthe spectrum, that for each optical active structure an optoelectronicdetector is provided in each of the respective assigned image planes fordetection of the optical image generated by the optical active structurein each of the wavelength bands blue, green and red, that each detectorcomprises at least one sensor element, such that at least one sensorelement uniquely defines a pixel of the optical image, the area of thepixel being substantially determined by the area of the separatedefining sensor element, that each detector in one of the image planesis adapted for defining a sample of the optical image in the wavelengthband corresponding to this image plane and with a number of pixels ineach sample determined by the number of sensor elements in the definingdetector, the digital image optimally being generated as an RGB colourimage with a spatial resolution determined by the number of pixels indistinct, by the sensor elements defined positions in the optical image.

Preferably according to the invention the optical active structures inthis case are refractive structures with a determined chromaticaberration or diffractive structures with a determined dispersion orcombinations of such structures, and particularly it is then preferredthat the refractive or diffractive structures are realized as lensletswith a diameter of at most 3 mm.

Further it is in that connection according to the invention preferredthat the total number of distinctly defined pixels in the optical imagein one of the wavelength bands is equal to the total number of sensorelements in the detectors for this wavelength band provided in thedetector device such that in this case a one-to-one relation between agiven pixel and its defining sensor element is present, whereby thedigital RGB colour image can be generated with a full sampling of theoptical image in each wavelength band and with three times oversamplingof the whole optical image in colours.

Finally, a method for digital electronic formatting of a recordedfull-format image according to the invention characterized by generatinga section or field of the full-format digital image by substantiallycontinuous or stepwise radial or axial contraction of the image towardsrespectively a convergence point or a convergence axis in the image, thecontraction of the image taking place digitally in a data processorprovided in the processor device and according to one or more determinedpixel-subtracting protocols and being effected by an in-camera orexternally provided operating device which is manoeuvred manually by acamera operator and automatically according to predetermined criteria,and by once again expanding formatted field radially or axially in thisway stepwise or continuously from respectively the convergence point orfrom the convergence axis towards a full-format image.

Preferably, according to the invention the formatting may be visualisedon the display device, the section or field caused by the formatting atany instant being displayed as a synthetic full-format image on thedisplay device, but with a real spatial resolution given by thecorresponding pixel subtraction value of the formatting.

Further, according to the invention a digital electronic zoom functionmay advantageously be implemented in the camera by the radialcontraction or expansion, the field format being determined asrespectively a telephoto, wide angle or macro format depending on thedistance between the scene and the image plane in the camera, and by adigital electronic pan function being implemented in the camera by theaxial contraction or expansion.

Further features and advantages of the present invention are disclosedby the remaining appended dependent claims.

The invention shall now be explained in more detail in the following bymeans of exemplary embodiments and with the reference to theaccompanying drawings, the figures of which are explained in more detailin the immediately succeeding section of the description.

FIGS. 1a, b show schematically a first embodiment of the optoelectroniccamera according to the invention, in a side view in FIG. 1a and frontview in FIG. 1b,

FIGS. 2a-c sections through different variants of the camera accordingto the invention,

FIGS. 3a, b schematically a second embodiment of the camera according tothe invention resp. entirely in a side and front view,

FIGS. 4a, b schematically a third embodiment of the camera according tothe invention, respectively in a side and front view, wherein opticalfilters are provided,

FIGS. 5a, b schematically a corresponding embodiment of the camera as inFIG. 4, respectively in a side view and front view, but wherein theoptical filters are provided in a different manner,

FIG. 6 an embodiment of a strip filter in an RGB system and as used inthe camera according to the invention,

FIG. 7 an embodiment of a mosaic filter in a complementary colour systemand as used in the camera according to the invention,

FIG. 8 schematically a fourth embodiment of the camera according to theinvention, in a side view,

FIG. 9a schematically a fifth embodiment of the camera according to theinvention,

FIG. 9b schematically detectors in the embodiment of the camera in FIG.9a,

FIG. 10a the implementation of the zoom function in the camera accordingto the invention, and

FIG. 10b the implementation of a pan function in the camera according tothe invention.

The basic concept for the camera according to the invention is shown inFIG. 1 which schematically renders a first embodiment in a side view inFIG. 1a and a front view in FIG. 1b. The camera employs a number ofoptical active structures, for instance in the form of microlenses orthe lenslets L, the camera objective system being shown as an array offour such lenses L₁-L₄. Each lens L generates an image of the scene tobe imaged with the desired total resolution in the final image. To eachof the lenses a detector device is assigned with respective detectorsD₁-D₄ provided on a back plane P which comprises for instance aprocessor, a memory etc. and where on the back side of the back planethere may be provided a display V for displaying the recorded image, thedisplay also functioning as a viewfinder. The common image plane I wherethe detectors D₁-D₄ are provided, is rendered spaced apart from thecommon infinite conjugate focal plane of the lens array, the focal planeF and the image plane I, of course, being coextensive for an imageobject which is located at infinite distance. Instead of attempting torecord all details for the light intensity distribution of the imageplane under a single lens with the high-density matrix oflight-sensitive sensor elements, which would lead to unrealistic sensorelement densities when the lens is small, the present invention employsa partial sampling of the image formed under each of the lenses L₁-L₄.In practice each detector D₁-D₄ samples via a plurality of sensorelements E in each detector a field of the optical image. In FIG. 1 asingle sensor element E is indicated in the detector D₁. Totally thedetectors D₁-D₄ have for instance 36 non-overlapping sensor elements Ewhich pixelate the optical image into 36 pixels. Consequently the sensorelements E also cover the whole area of the optical image such that itis detected by the detectors D₁-D₄ such that the partial samples fromeach of the detectors D₁-D₄ together forms a full sample of the image.

For each of the detectors D₁-D₄ as shown in FIG. 1b, the sensor elementsE form a sub-array in the image plane I of the four assigned lensesL₁-L₄. The sensor elements E hence determine the sampled areas of thesurface of each image plane I of the lenses L₁-L₄, as these areasmutually are positioned relative to the image such that they complementeach other in a composite mosaic picture. It shall be remarked that thedensity of the sampled areas in the image plane I does not need to beparticularly high, as each lens in an array of k lenses only samples 1/kof the total number of resolution elements in the final or compositeimage. This allows the possibility of using electronic array cameraswith moderate-to-low fill factors, as the fill factor is the value whichis obtained by dividing the light detecting portion of a pixel area withthe total pixel area. In addition to reducing the requirements for themanufacture of a light-sensor chip, a low fill factor also contributesto simplify the inclusion of image processing in the chip.

The optical active structures L do not necessarily need to be lenses,i.e. refractive structures, but may also be diffractive structures orreflective structures or combinations of such structures. If therefractive or diffractive structures are realized as lenslets, they mayhave a diameter of at most 3 mm and may be provided on a substantiallyrigid or flexible surface. This surface may be plane, curved ordouble-curved. For instance the optically active structures or thelenslets L may be provided as in FIGS. 2a-2 c, where FIG. 2a showslenses L on a curved transparent substrate S and assigned detectorsD_(n) provided on the backside of the substrate such that they registerwith the lenses L. In a backplane P under the detectors D_(n) (notshown) electronic components may be provided or, as shown, a display V.Correspondingly FIG. 2b shows how the optical active structures orlenses L may be provided on a facetted surface of the substrate S andagain with assigned detectors D_(n), while the backplane P may beprovided with a display V and/or not shown electronic components.

FIG. 2c shows the perhaps most preferred embodiment with lenslets Lprovided on a plane substrate S and with the detectors D_(n) on thebackside thereof. Again a display V and/or not shown electroniccomponents may be provided in or on a backplane P.

Sampling of specific areas in the image plane I may be achieved indifferent ways:

An opaque mask with light-transmitting areas or “windows” is provided inthe image plane I. Light incident through each window again falls on adedicated light-sensitive element which is provided under the window.The light-sensitive element is typically larger than the area which issampled by the window and may be much larger than the latter dependingon the number k of the lenses used in the array. This is in practiceachieved with the use of a spatial filter SF, such this is shown inFIGS. 3a and 3 b. The spatial filter SF is provided between a portionD_(n) of the detector device D and the lenses L, as shown in section inFIG. 3a and in front view in FIG. 3b. The spatial filter SF has windowsor openings A which register optically geometrically either with sensorelements E or with light-sensitive portions in the detector device D.For the sake of simplicity FIG. 3b discloses only a single lens L withan assigned spatial filter SF, the detector device D in practice beingrealised as a chip with a very large number of sensor elements E orlight sensitive portions and assigned to an array of lenses L.

The light-sensitive elements are in themselves formed and located in theimage plane such that they perform sampling functions. The areas betweeneach element is not sensitive to light because these areas areinherently insensitive to light or because they are masked by an opaquelayer provided directly on the chip surface.

As evident from the above, the number k of lenses must be matched to thedensity of the light-sensitive areas on the chip surface. This may be acritical bottleneck in the implementation of electronic miniaturecameras with flat profile. The minimum number of lenses which isnecessary depends on sensor technology desired to use in the camera andthe camera's specification with regard to form factor and image quality.

For instance, if it is supposed that a black/white picture shall berecorded and that a lens with resolution w (defocus circle diameter) inthe image plane is used, the most compact design is achieved when theeffective size of each light-sensitive sensor element in the detectormatches the resolution element w of the lens. For the miniature lensesone has typically w≧0.5 μm. The minimum size of sensor elements in thisarea may easily be adapted to the present technology for electronicarray cameras. The distance between the pixels in the electronic cameraslies typically in the range of 5 μm and above. This may be compared withthe required dimensions for the image, viz. n_(x)·w in the x directionand n_(y)·w in the y direction, which for a picture with one millionpixels and n_(x)=n_(y)=1000 becomes 500 μm·500 μm or more. Assuming thatthe light-sensitive areas of the sensor elements may be positioned witha mutual distance of for instance 10 μm, each lens may accommodate50·50=2500 pixels, and the minimum number of lenses which is necessarybecomes 400. In a quadratic lens array this implies 20·20 lenses.

If the camera according to the invention shall be used for recordingcolour images, it will with regard to the simplification ofmanufacturing the camera be desirable to avoid using colour filterswhich are pixelated with high precision.

FIG. 4a shows in a side view a means in an embodiment of the cameraaccording to the invention with the optical filters between the lensarray and the detector device. To each lens L₁, L₂, . . . there is inthis case provided a respective filter F1 _(R), F1 _(B), F1 _(G), eachof these filters as shown in front view of FIG. 4b being assigned torespectively groups of three and three lenses L₁,L₂,L₃; L₄,L₅,L₆;L₇,L₈,L₉ in the lens array. The optical filter for three and threelenses is provided for different spectral bands, denoted R, G, B, suchthat the filters together realizes a system for recording colour imagesin an RGB system Since each of the lenses L is assigned to a filter withonly one colour, all sensor elements in the detector D_(n) in the imageplane of this lens will sample this colour only. The other colourcomponents which are required for a full colour rendering of a givenpixel are sampled under the other lenses in a corresponding manner. Ifan RGB colour system is used in the camera according to the inventionconsequently three lenses with either an R filter, a G filter or a Bfilter, in the figure denoted as filters F1 _(R), F1 _(B), F1 _(G)respectively, each samples the spectral band in question in the sameportions of the image. As shown in FIG. 4b may this portion be arrangedin three separate, but mutually closely adjacent pixel areas, forinstance as covered by the detector areas D₁, D₄, D₇ such that acomplete overlapping is achieved. An advantage with the embodiment ofthis kind is that each optical active element or lens only must handle alimited wavelength range and hence may be optimized without thenecessity of bothering about chromatic aberrations. In a furtherembodiment of the invention there are used a number of filters withnarrow band-pass, i.e. it is requires more than the minimum number ofthree or four filters in order to provide a full colour rendering suchthat the desired spectral range is covered, while the lenses may beoptimized without taking chromatic aberrations in regard. This may be ofparticular importance when using diffractive optics, which may offerstructural and cost advantages compared with refractive optics, butwhich also often have a very large dispersion.

FIGS. 5a, 5 b show schematically an embodiment of a camera according tothe invention with corresponding filter means as in FIG. 4a and FIG. 4b,but here with the separate optical filters provided immediately beforethe separate detectors D_(n) in the detector device D. It shall, ofcourse, be understood that separate detectors D_(n) as shown in FIGS. 5aand 5 b may well be realized integrated on a detector chip and asportions of the chip, while the respective assigned filters F1 eachseparately may realize colour filters in for instance colour systemssuch as the RGB system. As shown in FIG. 5b each colour can then behandled by two filters with assigned detectors or detector portions. Forinstance could the filters F1 ₁ and F1 ₂ with assigned detectors D₁andD₂ handle the spectral band for red light the filters F1 ₁ and F1 ₂then, of course, realizing the R filter.

FIGS. 6 and 7 show different types of filters which may be used in anoptoelectronic colour image camera according to the present invention.FIG. 6 shows an embodiment of a strip filter in the RGB system. Thisfilter transmits alternately the red, green and blue spectral bands tothe respective assigned groups of detectors. Used in connection with theembodiment in FIG. 5 the colour strips RGB in the strip filter may beassigned to rows of sensor elements in the separate detector. Stripfilters provide an excellent colour rendering, but may in some casescause a reduced image resolution in a determined direction and possiblya reduced photometric response. FIG. 7 shows an embodiment of a mosaicfilter in a complementary colour system where the filter consists of amosaic of colour filters which alternately transmit one of thecomplementary colours cyan Cy, yellow Ye, green Gr or magenta Mg to thesensor element in a detector or to separately assigned detectors in adetector array. Full colour images are obtained by summing the signalsfrom four adjacent sensor elements or possibly detectors. That is to saythat signals from for instance adjacent pairs of linear detectors may beused for generating full colour images. Usually the image resolution andphotometric response are better than when using strip filters, but trueRGB output signals cannot be obtained using mosaic filters.Corresponding to the strip filters the separate fields in the mosaicfilters may separately be assigned to separate detectors, but may alsobe assigned to sensor elements in a single detector.

FIG. 8 shows an embodiment of the camera according to the inventionwhere the optical active structure of the lens L is given a chromaticaberration or dispersion such that light on different wavelengths λ₁, λ₂is refracted or dispersed to different image points s₁′, s₂′ inrespective image planes I₁, I₂. In the image planes I₁, I₂ respectivedetectors D₁, D₂ are provided such that a detection of the optical imageis obtained in two separate wavelength bands around the wavelengths λ₁,λ₂. The first detector D₁must then comprise sensors which are providedsuch that openings or windows are formed there between in the detectorD₁or otherwise the detector D₁in the areas between the sensors must betransparent for light centered around the wavelength λ₂ which hencereaches the detector D₂, is focused to the image plane I₂ and there isrecorded by the sensors in the detector D₂. Each of the detectors D₁, D₂will hence record an undersampled image, with a sampling factor of 0.5,such that the fields recorded by D₁, D₂ comprises the full sampled imageof the scene recorded with the lens L.

If a colour image is desirable, the camera according to the inventionmay comprise lenses and lens detectors provided as shown in FIG. 9a,which shows a single lens L. This lens L is given a chromatic aberrationor dispersion such that light on three different wavelengths λ₁, λ₂, λ₃are focused to image points s₁′, s₂′, s₃′ in three respective imageplanes I₁, I₂, I₃. In each image plane a respective detector D₁, D₂, D₃is provided, preferably with sensor element whose spectral selectivesensitivity is adapted respectively to the wavelengths λ₁, λ₂, λ₃. Thethree superpositioned provided detectors D₁, D₂, D₃ can then combinedgenerate the colour image in an RGB system. The detectors D₁, D₂ must berealized such that they are transparent for light outside the spectralbands which shall be detected in these detectors.

FIG. 9b shows schematically each of the detectors D₁, D₂, D₃ laterallyexploded and in a front view. Each detector is realized with 27 sensorelements and altogether the detector D₁, D₂, D₃ are made with 81 sensorelements, such that full pixel number for the optical image which isimaged by the lens L and detected by the detectors D₁, D₂, D₃ is 81. Foreach of the wavelengths λ₁, λ₂, λ₃ it is then with the lens L and thethree detectors D₁, D₂, D₃ obtained a sampling of the optical image withthe sampling factor of ⅓. The full sample RGB image will hence requirethree lenses with detectors provided as shown in FIG. 9a. Advantageouslythe detector D₁in the area which is not covered by the sensor elementsas shown in FIG. 9b may be made in a material which is transparent tolight on the wavelengths λ₂, λ₃. Light on the wavelength λ₂ will hencepass through and be focused to the image plane I₂ where the detector D₂is provided. The detector D₂ is preferably correspondingly made in amaterial which is transparent for light on the wavelength λ₃ such thatlight on this wavelength may pass through the detector D₂ where it isnot covered by the sensor element and be focused to the image plane I₃where D₃ is provided.

There shall now be given a more detailed description of differentoptical properties and realizable technical features of the cameraaccording to the invention.

For applications where it is desirable that the camera shall be simpleand inexpensive, it may be expedient to use a fixed-focus system, i.e.an optical imaging system without mechanical moving parts. For a lenswith focal length f and f′ in respectively the object space and imagespace, the equation for a thin lens may be written

x·x′=f·f′  (7)

Here x and x′ is the distance along the optical axis from the infintelyconjugate focal points to respectively the object point at s and theimage point at s′:

x=s −f  (8)

x′=s′−f  (9)

From equations (7), (8) and (9) it is seen that an axial objectdisplacement δs leads to an axial image displacement δs′ relative to theimage plane, as, if s>>f,

δs′=−f·f′·δs/s ²  (10)

From equation (10) it is seen that the image position becomes lessdependent of the object distance s as the latter increases. Thisrelationship is well known to amateur photographers. Further it is seenthat for a given object distance s the image position to lesser degreedepends on the object distance as the focal lengths f and f′ becomeshorter.

The latter relationship is of special interest in the present connectionwhere the lens has focal lengths two to three magnitudes less thantraditional photographic systems. On the other hand the defocustolerance Δs′ of the image plane for diffraction limited optics obeyingequation (1) above will be limited by the physical dimensions of theoptics, and Δs′ shall in the present case be comparable to that whichmay be attained with traditional photographic systems.

This has a dramatic impact on the depth of field Δs. Assuming forsimplicity f≅f′, equation (10) may be written

Δs≅−(s/f)² ·Δs′  (11)

The depth of field for a given Δs′ in other words scales as the inversesquare of focal length f. As an example one may consider a camera withfixed focus at infinite, i.e. an image plane with s′=f′=f. If thedefocus tolerance in the image plane Δs′, the closest object distances_(min) is then defined by the standard lens equation

1/s+1/s′=1/f′  (12)

which at the object distance s=s_(min) becomes

1/s _(min)+1/(f÷Δs′)=1/f  (13)

and hence for f>>Δs′,

s _(min) =f ² /Δs′  (14)

Assuming for instance that f=1 mm, Δs′=1 μm, one consequently obtainss_(min)=10³ mm and a camera with fixed focus gives sharply definedimages in the focal plane from infinity and down to 1 m. By selecting anominal optimal focus for a finite distance, i.e. closed than infinity,s_(min) may be further reduced.

If the optoelectronic camera according to the invention is realized withpossibilities for digital or software controlled image processing, anumber of advantages may be obtained. Particularly it must be remarkedthat electronic imaging as compared with traditional film-based imaginggives the possibility of a simple and direct manipulation of the imageinformation by means of suitable software before the result, thefinished picture, is presented. In certain cases a processing of thiskind may be performed directly “on-chip”, i.e. in close physicalproximity to the detector and with the use of electronic components andcircuits integrated with the latter, for instance a CMOS basedarchitecture. Commercial, “camera-on-a-chip” components and systems cannow be bought with different types of processing on the chip, includingthresholding and correlation analysis between the pixels such as contourdefinition. Below certain types of image processing which are particularto the present invention shall be discussed.

The basic realization of the optoelectronic camera according to theinvention makes it possible to employ light-sensitive detector arrayswhich extend over a relatively large area and comprise a large number ofpixels. This means that two subgroups of pixels may be selected suchthat they represent sections of a larger picture and hence there may beprovided a zoom function, a pan function or motion compensatingfunctions.

FIG. 10a shows how a section of a full-format image may be contractedtowards a convergence point in the image. The contraction may take placestepwise or continuously radially by being realized with softwarecontrol by means of a processor provided in the camera and using apredetermined pixel-subtracting protocol. Section 1 and section 2 inFIG. 10a represent zoom pictures, but with a reduced number of pixelsrelative to the total number of pixels in the full-format image. Ifsection 1 and section 2 are reproduced on the display, they will beblown up to a format which fills the display and software may then beused for generating the zoom image from a synthetic full-format image,but with the same resolution as the full-format image by interpolatingpixels in the enlarged sections, such that the zoom images representedby sections 1 or 2 may appear with seemingly the same resolution as thereal full-format image.

FIG. 10b shows how a pan function may be implemented in the camera byallowing the full-format image to contract axially towards a convergenceaxis, such that different pan image sections 1 and 2 are formed. Theconvergence axis is in this case the horizontal bisecting line of thefull-format image.

In the optoelectronic camera according to the invention it is aparticular feature that information is recorded by means of two or moreoptical systems which are mutually displaced in the lateral direction.For objects which are located closer than infinity, this means thatparallax problems may be present. In simple imaging cases the parallaxcauses a lateral displacement of the image in the image plane relativeto the image position for objects at infinity. This displacement variesin a systematic fashion from lens to lens in the array and becomeslarger the nearer the camera the object is located. The displacement mayin a simple manner be compensated by selecting light-sensitive elements,i.e. sensor elements, which are correspondingly displaced when the imageis electronically synthesized. This may be done in different ways. Onemethod is to taking a particular degree of parallax into considerationfor all images which are to be synthesized, in which case an optimumobject distance is selected for the most relevant imaging task. Anothermethod is correlating different images in the memory of the camera andoptimizing the selection of light-sensitive areas for the best resultingimage.

It will also be possible to implement an autofocus function wherein theinherent depth of field for an optical system with mechanical fixedfocus is insufficient. This can take place in similar manner asmentioned in connection with the parallax compensation, by choosing anoptimal object distance for an image to be synthesized. In thatconnection the inherent parallax error using a lens array, i.e. thedisplacement of object in the image plane, may be used for a distancemeasurement.

Finally, specific examples of embodiments of the optoelectronic cameraaccording to the invention shall be discussed.

EXAMPLE 1

Flexible Microlens Camera

Reference is made to one of the FIGS. 2a-2 c. The camera is realized asa sandwich with a large number of microlenses 2 located in a thinflexible sheet. The latter is attached to another flexible sheet whereinthe detectors D_(n) are provided in a controlled pattern. The lens sheetmay be made of a monolithic piece of plastic material wherein thelenslets are formed by plastic deformation, etching or by depositing amaterial on a plane substrate. Alternatively a lenslet sheet maycomprise a number of individual lenslets immobilised in a flexible,planar matrix.

Plastic detectors provided as arrays on flexible substrates haverecently been realized based on the use of conjugated polymers.Responsivity and spectral response are very good and compatible withapplications which demand imaging with high quality.

The sandwich construction which realizes the camera may be attached toeither plane and/or curved surfaces, for instance for use in areas ofsurveillance. By for instance curving the sandwich structure into acylinder, an image field of 360° may be obtained, which will make amechanical pan function superfluous.

EXAMPLE 2

Camera with Diffractive Microlenses

Reference is made to FIG. 2c, as it is to be understood that eachlenslet L is a diffractive lens and in this case with an assignedoptical filter with a band-pass range which allows imaging through thediffractive lens without significant chromatic aberrations. In order toobtain spectral coverage over a sufficiently broad wavelength range, aseries of lenslets with complementary band-pass filters may be used. Thenumber of band-pass filters may be very large such that a spectralcoverage of a broad spectral range is obtained with individual filterswhich have a very narrow bandwidth. For instance the embodiment as shownin FIG. 2c may in this case practically be implemented as shown in FIGS.5a and 5 b by individual filters being provided behind each lens L, butin front of the assigned detectors D_(n).

In addition to realizing a very flat surface profile for the camera theuse of diffractive lenslets gives large flexibility with regard tocontrolling the imaging properties of the individually lenses. Thisallows further improvements of the camera architecture mentioned above.For instance certain lenses in the array may be optimized in order toimage chosen peripheral areas of the image, i.e. the rays which enter ata large angle to the optical axis of the camera. By using standardmethods for mass production the diffractive lenslet arrays whichcomprise a very large number of individual lenslets with specialproperties, may be fabricated cheaply and reliably.

EXAMPLE 3

Ultraminiature Camera

Once again it is supposed that the camera is implemented with a basicstructure as in FIG. 2c. In this case detectors in array configurationmay be used by employing a passive addressing architecture as disclosedin Norwegian patent application 97 3390 and which hereby is incorporatedas reference. This architecture is particularly suited for usinglight-sensitive polymers in hybrid silicon components, or componentswherein the electronic circuits and mechanical supporting elementswholly or partly are made in organic materials.

This makes it possible to form light-sensitive areas in an image planewith an area density which exceeds that which is attainable withelectronic light-sensor arrays based on prior art (for instance APS andCCD), by one to two orders of magnitude. This again implies that thenumber of lenslets which is necessary in order to provide images withhigh quality can be correspondingly reduced. If a lens handles only oneprimary colour, this implies in its ultimate consequence that at leastthree lenslets are required.

As disclosed above the complexity and physical size of these lenses willbe greatly reduced compared with achromatic lenses with correspondingmodulation transfer function performance (MTF performance), leading tolenses with typical dimensions in 1 mm³ range. Hence it will be possibleto realize an optoelectronic full-colour camera with high quality withina total form factor of a few mm³.

What is claimed is:
 1. An optoelectronic camera, comprising: an opticalobjective system for imaging a scene recorded by the camera as anoptical image substantially in an image plane of the objective system,including: an optoelectronic detector device substantially provided inthe image plane for detecting the optical image and on basis of thedetection outputting output signals, a processor device connected withthe detector device for converting and processing the output signals ofthe detector device in order to reproduce the detected image in digitalform, and a memory device connected with the processor device forstoring the digital image or for storing, displaying or possibleadditional processing on external devices adapted for these purposes andwhereto the camera may be connected, an array of two or more opticalactive structures, each optical active structure is adapted forgenerating optical images of the recorded scene on areas of theobjective system image plane uniquely assigned to the respective opticalactive structure, wherein at least one optoelectronic detector isprovided for each optical active structure in its respective assignedarea or image plane, all detectors being included in the detector deviceof the camera, each detector including at least one sensor elementuniquely defining a pixel of the optical image, the area of the pixelsubstantially being determined by the area of the separate definingsensor element, wherein each detector is adapted to define a sample ofthe optical image with a number of pixels in each sample determined by anumber of sensor elements in the defining detector, the digital imageoptimally being generated by all samples and with a spatial resolutiondetermined by the number of pixels in distinct positions in the opticalimage defined by the sensor elements, wherein the ratio between thesensor element area of the detector with a total of the detector area issubstantially less than
 1. 2. Optoelectronic camera according to claim1, wherein the optical active structures are refractive structures ordiffractive structures or reflective structures or combinations of suchstructures.
 3. Optoelectronic camera according to claim 2, wherein therefractive or the diffractive structures are formed as lenslets with adiameter of at most 3 mm.
 4. Optoelectronic camera according to claim 1,wherein the objective system with the optical active structures forms asubstantially rigid or flexible surface.
 5. Optoelectronic cameraaccording to claim 4, wherein the substantially rigid or flexiblesurface is a plane, curved or double-curved surface.
 6. Optoelectroniccamera according to claim 1, wherein each detector comprises an array oftwo or more sensor elements such that each sensor element in the arraydefines a spatially distinct pixel in the optical image. 7.Optoelectronic camera according to claim 1, wherein the sensor elementsall have identical form factor, and that the area of the optical imageexpressed in pixels hence is given by the ratio between the geometricarea of the optical image and the geometric area of a single sensorelement.
 8. Optoelectronic camera according to claim 1, wherein thetotal number of distinctly defined pixels in the optical image is equalto the total number of sensor elements in the detector device, such thata one-to-one relation between a given pixel and its defining sensorelement is present, whereby the digital image may be generated by a fullsampling of the optical image.
 9. Optoelectronic camera according toclaim 1, wherein the total number of distinctly defined pixels in theoptical image is smaller than the total number of sensor elements in thedetector device, such that a one-to-many relation between a given pixeland its defining sensor element or sensor elements is present, wherebythe digital image may be generated by an oversampling of the opticalimage.
 10. Optoelectronic camera according to claim 1, wherein two ormore detectors define identical spatial samples of the optical image.11. Optoelectronic camera according to claim 1, further comprising: oneor more spatial filters provided in front of the objective system and/orbetween the objective system and the detector device.
 12. Optoelectroniccamera according to claim 11, wherein the spatial filter is a spatiallight modulator.
 13. Optoelectronic camera according to claim 12,wherein the spatial light modulator is a controllable electroopticallight modulator.
 14. Optoelectronic camera according to claim 1, furthercomprising: one or more optical filter means provided in front of theobjective system and/or between the objective system and the detectordevice.
 15. Optoelectronic camera according to claim 14, wherein theoptical filter means comprises separate, spectral selective filterswhich separately are assigned to either each optical active structure orgroups of optical active structures, or to the detector or detectors ofthe detector device assigned to each optical active structure. 16.Optoelectronic camera according to claim 15, wherein the optical filtermeans is adapted for transmitting in two or more separate wavelengthbands by each spectral-selective filter transmitting in a separatewavelength band, the number of filters which transmit in each of theseparate wavelength bands substantially being identical. 17.Optoelectronic camera according to claim 16, wherein the separatewavelength bands in adjacent or not adjacent bandwidth relationshipcombined at least cover the visual part of the spectrum. 18.Optoelectronic camera according to claim 16, wherein the separatewavelength bands are selected such that the optical filter means forms aprimary colour filter means or an RGB filter means.
 19. Optoelectroniccamera according to claim 16, wherein the separate wavelength bands areselected such that the optical filter means forms a complementary colourfilter means.
 20. Optoelectronic camera according to claim 17, whereinthe spectral-selective filters of the filter means separately areassigned or superpositioned to the detector or detectors provided foreach optical active structure, and wherein the spectral-selective filteris a strip filter which is adapted for transmitting in two or moreseparate wavelength bands by each strip transmitting in a givenwavelength band, the number of strips which transmits in each of thewavelength bands substantially being identical.
 21. Optoelectroniccamera according to claim 10, wherein each strip in a strip filter isassigned to a respective row or column of sensor elements in thedetector or detectors.
 22. Optoelectronic camera according to claim 20,wherein each strip filter is a primary colour filter or an RGB filter.23. Optoelectronic camera according to claim 15, wherein thespectral-selective filters of the filter means separately are assignedor superpositioned to the detector or detectors provided for eachoptical active structure, and the spectral selective filter is a mosaicfilter which is adapted for transmitting in two or more separatewavelength bands by each filter segment in the mosaic filtertransmitting in a given wavelength band, the number of filter segmentswhich transmit in each of the wavelength bands substantially beingidentical.
 24. Optoelectronic camera according to claim 23, wherein eachfilter segment in the mosaic filter is assigned to a respective sensorelement or respective sensor elements in the detector or detectors. 25.Optoelectronic camera according to claim 23, wherein each mosaic filteris a complementary colour filter.
 26. Optoelectronic camera according toclaim 1, wherein the detector device comprises detectors realized in oneof the following technologies, viz. CCD (charge-coupled device)technology, CID (charge-injected device) technology, APS (active pixelsensor) technology or PMSA (sensor array in passive matrix) technology.27. Optoelectronic camera according to claim 26, wherein the detector isrealized in PMSA technology, and the detector is realized as a thin-filmcomponent or a hybrid component, and that the detector is adapted forparallel read-out of the output signals from the sensor elements over apassive electrode array for unique addressing of each separate sensorelement.
 28. Optoelectronic camera according to claim 27, wherein thedetector is made wholly or partly of organic semiconducting orelectrical isolating materials, including plastic materials andsemiconducting oligomers or polymers.
 29. Optoelectronic cameraaccording to claim 28, wherein the organic materials wholly or partlytransmit light in at least the visual part of the spectrum, and that thedetector in the area between its sensor elements is transparent ortranslucent in this spectral range.
 30. Optoelectronic camera accordingto claim 28, wherein the electrode array of the detector wholly orpartly is transparent or translucent in at least the visual range of thespectrum.
 31. Optoelectronic camera according to claim 1, wherein theoptical active structures are realized with a determined chromaticaberration or dispersion, such that each optical active structure fortwo or more separate wavelength bands spectral-selectively generates theoptical image in each wavelength band substantially on correspondingsubstantially congruent image planes superpositioned spaced apart in theray direction, and that for each optical active structure in each ofthese image planes a detector for spectral-selective detection of theoptical image is provided such that for each optical active structure oneach image plane a sample in the spatial domain and a sample in thefrequency domain are defined, the resolution in the frequency domainsubstantially being determined by the number of separate wavelengthbands with a respective assigned detector, whereby the optical imagedetected by the detector device may be generated as a multispectraldigital colour image with the use of a selected suitable colour system.32. Optoelectronic camera according to claim 31, wherein three separatesuperpositioned detectors are provided for each optical activestructure, respectively in the image plane for three separate wavelengthbands assigned to a three-colour system.
 33. Optoelectronic camera,particularly for recording colour images and even more particularly forrecording colour images in an RGB system, comprising an opticalobjective system for imaging a scene recorded by the camera as anoptical image substantially in an image plane of the objective system,an optoelectronic detector device substantially provided in the imageplane for detecting the optical image and on basis of the detectionoutputting output signals, a processor device connected with thedetector device for converting and processing the output signals of thedetector device in order to reproduce the detected image in digital formand possibly for displaying this in real time on a display deviceoptionally provided in the camera and connected with the processordevice, and a memory device connected with the processor device forstoring the digital image for displaying on the optional display devicewhich also may be connected with the memory device, or for storing,displaying or possible additional processing on external devices adaptedfor these purposes and whereto the camera temporarily or permanently isconnected, wherein the camera objective system is formed by an array oftwo or more optical active structures, each optical active structure hasa determined chromatic aberration or dispersion such that the locationof its focal point depends on the wavelength of the light, each opticalstructure is adapted for generating spectral-selectively optical imagesof the recorded scene on areas of three separate superpositioned imageplanes of the objective system, said areas being uniquely assigned torespective optical active structures, a first image plane forming afirst optical image on a wavelength band in the blue portion of thespectrum, and a second image plane forming a second optical image on awavelength band in the green portion of the spectrum and a third imageplane forming a third optical image on a wavelength band in the redportion of the spectrum, that for each optical active structure anoptoelectronic detector is provided in each of the respective assignedimage planes for detection of the optical image generated by the opticalactive structure in each of the wavelength bands blue, green and red,that each detector including at least one sensor element, such that atleast one sensor element uniquely defines a pixel of the optical image,the area of the pixel being substantially determined by the area of theseparate defining sensor element, that each detector in one of the imageplanes is adapted for defining a sample of the optical image in thewavelength band corresponding to this image plane and with a number ofpixels in each sample determined by the number of sensor elements E inthe defining detector (D_(n)), the digital image optimally beinggenerated as an RGB colour image with a spatial resolution determined bythe number of pixels, by the sensor elements defined positions in theoptical image.
 34. Optoelectronic camera according to claim 33, whereinthe optical active structures are refractive structures with adetermined chromatic aberration or diffractive structures with adetermined dispersion or combinations of such structures. 35.Optoelectronic camera according to claim 34, wherein the refractive ordiffractive structures are realized as lenslets with a diameter of atmost 3 mm.
 36. Optoelectronic camera according to claim 33, wherein thetotal number of distinctly defined pixels in the optical image in one ofthe wavelength bands is equal to the total number of sensor elements inthe detectors for this wavelength band provided in the detector devicesuch that in this case a one-to-one relation between a given pixel andits defining sensor element is present, whereby the digital RGB colourimage can be generated with a full sampling of the optical image in eachwavelength band and with three times oversampling of the whole opticalimage in colours.
 37. Optoelectronic camera according to claim 33,wherein the total number of distinctly defined pixels of the opticalimage in one of the wavelength bands is smaller than the total number ofsensor elements in the detectors for this wavelength band provided inthe detector device, such that in this case a one-to-many relationbetween a given pixel and its defining sensor element or sensor elementsin this case is present, whereby the digital RGB colour image can begenerated with an oversampling in each wavelength band and with a totaloversampling of the optical image equal to the sum of the oversamplingfactor in each wavelength band.
 38. A method for digital electronicformatting of a recorded full-format optical image in an optoelectroniccamera according to claim 1, wherein the recorded optical image isstored as a digital image in a memory in a processor device provided inthe camera and may be displayed on a display device connected to theprocessor device, further comprising, generating a section or field ofthe full-format digital image by substantially continuous or stepwiseradial or axial contraction of the image towards respectively aconvergence point or a convergence axis in the image, the contraction ofthe image taking place digitally in a data processor provided in theprocessor device and according to one or more determinedpixel-subtracting protocols and being effected by an in-camera orexternally provided operating device which is manoeuvred manually by acamera operator and automatically according to predetermined criteria,and by once again expanding formatted field radially or axially in thisway stepwise or continuously from respectively the convergence point orfrom the convergence axis towards a full-format image.
 39. A methodaccording to claim 38, wherein the formatting is visualised on thedisplay device, the section or field caused by the formatting at anyinstant being displayed as a synthetic full-format image on the displaydevice, but with a real spatial resolution given by the correspondingpixel subtraction value of the formatting.
 40. A method according toclaim 38, wherein a digital electronic zoom function is beingimplemented in the camera by the radial contraction or expansion, thefield format being determined as respectively a telephoto, wide angle ormacro format depending on the distance between the scene and the imageplane in the camera, and by a digital electronic pan function beingimplemented in the camera by the axial contraction or expansion. 41.Method according to claim 38, wherein the convergence point and theconvergence axis default automatically and are chosen respectively bythe intersection between the optical axis and the image plane or thehorizontal bisecting line of the image plane, and by the convergencepoint and the convergence axis being manually selected over theoperating device as respectively an arbitrary point or an arbitrary axisof the image.
 42. The optoelectronic camera of claim 1, wherein thedetected image is displayed in real time on a display device provided inthe camera and connected with the processor device.